The present invention relates to a camera apparatus, and in particular, to an endless camera apparatus using wireless data transmission.
Monitor camera apparatuses using imaging devices have been actually employed in many cases to monitor an invader or an invading object (which will be referred to as an invading object hereinbelow) making an invasion upon, for example, a public building, a public place, a hospital, a bank, a shop such as a supermarket, or a zone which any unauthorized person is forbidden to enter such as a dam, a base, or an airport. When such monitor camera apparatus is employed to a remote monitor system, the monitor area to be monitored by the system can be easily confirmed by visually checking images produced by the monitor camera apparatus. It is therefore possible to construct a high-quality warning monitor system capable of appropriately and rapidly cope with various states according to situations monitored by the monitor camera apparatus.
However, to monitor the monitor target area for a long period of time by remote control, high reliability is required for such monitor camera system. Particularly, when the monitoring apparatus is installed in a place requiring high security such as a bank, a base, or an airport or a place at a high altitude or a remote place such as a dam or a port, maintenance of the apparatus is quite troublesome. There consequently exists a demand for a monitor camera apparatus in which the human power and time required for the maintenance and inspection thereof can be reduced to the maximum extent.
To fully achieve the monitoring function, the monitor camera apparatus requires a wide monitor zone depending on places. For this purpose, the monitor camera apparatus includes a driver module to drive the camera itself in a pan direction (horizontal direction) and in a tilt direction (direction of angle of elevation) to widely change the visual field range of the monitor camera apparatus. Particularly, there recently exists a demand for a camera apparatus which covers a wide monitor range to track an invading object by use of an endless rotation in a pan direction.
On the other hand, the camera apparatus generally includes a coaxial cable to transmit a video signal from a camera section to shoot an object as well as a camera control signal and to supply power for the operation of the camera section. The coaxial cable is connected to a fixing part and a moving part in the configuration. That is, a first end of the coaxial cable is connected to the fixing part and a second end thereof is connected to the moving part. For example, the camera section and the lightening device are configured to be united with each other onto a rotary axis which rotates together with the camera section so that the camera section and the lightening device move as one unit. However, the wiring cables of the camera section, the lightening device, and the like are disposed on the substrate of the fixing part which does not rotate together with the camera section. Therefore, in the monitor camera apparatus in which the visual field is to be frequently changed as described above, the wiring cables are twisted and are repeatedly expanded and contracted. This causes disconnection or connection failure of the wiring cables. In the camera apparatus connected by wiring cables as above, it is not possible to conduct the endless rotation in the pan direction.
Such camera apparatus to implement the endless rotation has already been put to practical uses. FIG. 5 is a diagram showing an outline of the configuration of a camera apparatus of a conventional type using slip rings. The camera apparatus of FIG. 5 includes a moving part 501 and a fixing part 502. The moving part 501 includes a camera section 503 to shoot an image of an object such as an invader or an invading object, a signal processing section 504 which appropriately processes the video signal of the image of the object shot by the camera section 503 and which converts the video signal into a signal for transmission, a camera driver section 505 to drive the camera section 503 in the pan and tilt directions, a power source section 506 to supply power to the camera section 503, the signal processing section 504, and the driver section 505 and so on. The moving section 501 can conduct endless rotation about a rotary axis, not shown.
The fixing part 502 includes a signal processing section 508 to appropriately process the video signal from the signal processing section 504, an interface (I/F) section 510, a power source section 509 and so on. The fixing part 502 is attached to a place at a high altitude, for example, on a wall or a ceiling. Reference numeral 507 indicates slip rings S1, S2, and S3 each of which includes as well known a fixed conductor and a rotating conductor or a rotating (or a rotary brush), not shown. Reference numeral 511 is an input/output terminal for the video and control signals and reference numeral 512 is a power input terminal.
Operation of the configuration will be briefly described. Alternating-current (ac) power inputted from the power terminal 512 is converted by the power source section 509 into, for example, direct-current (dc) power to be supplied via the slip ring S3 to the power source section 506. Although not shown in FIG. 5, it is to be appreciated that power is supplied from the power source section 506 respectively to the camera section 503, the signal processing section 504, the driver section 505 and so on. Control signals for the camera section 503 and the driver section 505 are inputted from the input terminal 511 to be fed via the interface section 510 to the signal processing section 508. The control signals are separated in the signal processing section 508 and are applied via the slip ring S2 respectively to the camera section 503 and the driver section 505. The control signals are used, for example, to adjust the focus and the color balance in the optical system of the camera section 503 and to adjust the pan and tilt angles in the driver section 505. The video signal of the image of the object shot by the camera section 503 is appropriately processed by the signal processing section 504 to be supplied via the slip ring S1 to the signal processing section 508 and is then outputted via the interface section 510 from the input/output terminal 511.
As described above, in the camera apparatus employing slip rings, the moving part 501 including the camera section 503 can conduct endless rotation. It is therefore possible to configure a camera apparatus which covers a wide range as a monitor device. However, as can be seen from FIG. 5, when the video data and the control data from the camera section are supplied via the slip rings, the transmission data is limited to analog data of low resolution or control data with a small amount of information. For example, to transmit image data of high resolution and data of a large capacity, it is required to use digital signals in a range from about several megahertz (MHz) to about 30 MHz. This consequently leads to a problem that the digital signals of such high frequency cannot be transmitted via the slip rings. There hence exists a demand for the implementation of a camera apparatus which can conduct the endless rotation and which can transmit image data of high resolution and data of a large capacity.
The technique described above are described in, for example, JP-A-9-284612.